wifi: iwlwifi: pcie: synchronize IRQs before NAPI

When we want to synchronize the NAPI, which was added in
commit 5af2bb3 ("wifi: iwlwifi: call napi_synchronize()
before freeing rx/tx queues"), we also need to make sure we
can't actually reschedule the NAPI. Yes, this happens while
interrupts are disabled, but interrupts may still be running
or pending. Also call iwl_pcie_synchronize_irqs() to ensure
we won't reschedule the NAPI.

Fixes: 4cf2f59 ("iwlwifi: queue: avoid memory leak in reset flow")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20231017115047.a0f4104b479a.Id5c50a944f709092aa6256e32d8c63b2b8d8d3ac@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c

@@ -161,6 +161,7 @@ void _iwl_trans_pcie_gen2_stop_device(struct iwl_trans *trans)
 	if (test_and_clear_bit(STATUS_DEVICE_ENABLED, &trans->status)) {
 		IWL_DEBUG_INFO(trans,
 			       "DEVICE_ENABLED bit was set and is now cleared\n");
+		iwl_pcie_synchronize_irqs(trans);
 		iwl_pcie_rx_napi_sync(trans);
 		iwl_txq_gen2_tx_free(trans);
 		iwl_pcie_rx_stop(trans);

drivers/net/wireless/intel/iwlwifi/pcie/trans.c

@@ -1264,6 +1264,7 @@ static void _iwl_trans_pcie_stop_device(struct iwl_trans *trans)
 	if (test_and_clear_bit(STATUS_DEVICE_ENABLED, &trans->status)) {
 		IWL_DEBUG_INFO(trans,
 			       "DEVICE_ENABLED bit was set and is now cleared\n");
+		iwl_pcie_synchronize_irqs(trans);
 		iwl_pcie_rx_napi_sync(trans);
 		iwl_pcie_tx_stop(trans);
 		iwl_pcie_rx_stop(trans);